One or more embodiments relate to a nonvolatile memory device and a method of operating the same and, more particularly, to a nonvolatile memory device and a method of operating the same, wherein an error checking and correction (ECC) processing is performed in a read operation.
A nonvolatile memory device has the property that data stored therein is retained even if the supply of power is stopped. A NAND flash memory device is one of the representative nonvolatile memory devices.
The nonvolatile memory device includes memory cells for storing data. If the degree of integration of the nonvolatile memory devices increases, the electrical properties of the nonvolatile memory devices deteriorate because the size of the memory cells decreases. For example, a memory cell having poor properties resulting from problems in the process may not properly store data in a program operation, or data stored in the memory cell may not be properly erased in an erase operation. In this case, an invalid block processing for preventing a memory cell block, including invalid memory cells, from being used is carried out.
As another example, data stored in the memory cell having poor properties is altered because of, for example, the leakage current. Furthermore, when a read operation is repeatedly performed after data is stored in memory cells, the threshold voltages of the memory cells may be changed by a pass voltage applied to the memory cells during the read operation, thereby changing data stored in the memory cells. If the data retention characteristic is degraded as described above, reliability of the device is compromised, and data stored in the device may not be read correctly.